/Engine/Source/Developer/DesktopPlatform/Public/IDesktopPlatform.h
Finds all the projects which the engine (given by an identifier) has a record of. This includes all the recently opened projects, projects in the default project directory, and so on.
Path to the folder
bool EnumerateProjectsKnownByEngine ( const [FString](API\Runtime\Core\Containers\FString) & Identifier, bool bIncludeNativeProjects, [TArray](API\Runtime\Core\Containers\TArray)< [FString](API\Runtime\Core\Containers\FString) > & OutProjectFileNames )